--- /dev/null
+From c58a584f05e35d1d4342923cd7aac07d9c3d3d16 Mon Sep 17 00:00:00 2001
+From: Vineet Gupta <vgupta@synopsys.com>
+Date: Fri, 5 Oct 2018 12:48:48 -0700
+Subject: ARC: clone syscall to setp r25 as thread pointer
+
+From: Vineet Gupta <vgupta@synopsys.com>
+
+commit c58a584f05e35d1d4342923cd7aac07d9c3d3d16 upstream.
+
+Per ARC TLS ABI, r25 is designated TP (thread pointer register).
+However so far kernel didn't do any special treatment, like setting up
+usermode r25, even for CLONE_SETTLS. We instead relied on libc runtime
+to do this, in say clone libc wrapper [1]. This was deliberate to keep
+kernel ABI agnostic (userspace could potentially change TP, specially
+for different ARC ISA say ARCompact vs. ARCv2 with different spare
+registers etc)
+
+However userspace setting up r25, after clone syscall opens a race, if
+child is not scheduled and gets a signal instead. It starts off in
+userspace not in clone but in a signal handler and anything TP sepcific
+there such as pthread_self() fails which showed up with uClibc
+testsuite nptl/tst-kill6 [2]
+
+Fix this by having kernel populate r25 to TP value. So this locks in
+ABI, but it was not going to change anyways, and fwiw is same for both
+ARCompact (arc700 core) and ARCvs (HS3x cores)
+
+[1] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/arc/clone.S
+[2] https://github.com/wbx-github/uclibc-ng-test/blob/master/test/nptl/tst-kill6.c
+
+Fixes: ARC STAR 9001378481
+Cc: stable@vger.kernel.org
+Reported-by: Nikita Sobolev <sobolev@synopsys.com>
+Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/arc/kernel/process.c | 20 ++++++++++++++++++++
+ 1 file changed, 20 insertions(+)
+
+--- a/arch/arc/kernel/process.c
++++ b/arch/arc/kernel/process.c
+@@ -153,6 +153,26 @@ int copy_thread(unsigned long clone_flag
+ task_thread_info(current)->thr_ptr;
+ }
+
++
++ /*
++ * setup usermode thread pointer #1:
++ * when child is picked by scheduler, __switch_to() uses @c_callee to
++ * populate usermode callee regs: this works (despite being in a kernel
++ * function) since special return path for child @ret_from_fork()
++ * ensures those regs are not clobbered all the way to RTIE to usermode
++ */
++ c_callee->r25 = task_thread_info(p)->thr_ptr;
++
++#ifdef CONFIG_ARC_CURR_IN_REG
++ /*
++ * setup usermode thread pointer #2:
++ * however for this special use of r25 in kernel, __switch_to() sets
++ * r25 for kernel needs and only in the final return path is usermode
++ * r25 setup, from pt_regs->user_r25. So set that up as well
++ */
++ c_regs->user_r25 = c_callee->r25;
++#endif
++
+ return 0;
+ }
+
--- /dev/null
+From 98b8cd7f75643e0a442d7a4c1cef2c9d53b7e92b Mon Sep 17 00:00:00 2001
+From: Michal Suchanek <msuchanek@suse.de>
+Date: Sat, 27 May 2017 17:46:15 +0200
+Subject: powerpc/fadump: Return error when fadump registration fails
+
+From: Michal Suchanek <msuchanek@suse.de>
+
+commit 98b8cd7f75643e0a442d7a4c1cef2c9d53b7e92b upstream.
+
+ - log an error message when registration fails and no error code listed
+ in the switch is returned
+ - translate the hv error code to posix error code and return it from
+ fw_register
+ - return the posix error code from fw_register to the process writing
+ to sysfs
+ - return EEXIST on re-registration
+ - return success on deregistration when fadump is not registered
+ - return ENODEV when no memory is reserved for fadump
+
+Signed-off-by: Michal Suchanek <msuchanek@suse.de>
+Tested-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
+[mpe: Use pr_err() to shrink the error print]
+Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
+Cc: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/powerpc/kernel/fadump.c | 23 +++++++++++++++--------
+ 1 file changed, 15 insertions(+), 8 deletions(-)
+
+--- a/arch/powerpc/kernel/fadump.c
++++ b/arch/powerpc/kernel/fadump.c
+@@ -360,9 +360,9 @@ static int __init early_fadump_reserve_m
+ }
+ early_param("fadump_reserve_mem", early_fadump_reserve_mem);
+
+-static void register_fw_dump(struct fadump_mem_struct *fdm)
++static int register_fw_dump(struct fadump_mem_struct *fdm)
+ {
+- int rc;
++ int rc, err;
+ unsigned int wait_time;
+
+ pr_debug("Registering for firmware-assisted kernel dump...\n");
+@@ -379,7 +379,11 @@ static void register_fw_dump(struct fadu
+
+ } while (wait_time);
+
++ err = -EIO;
+ switch (rc) {
++ default:
++ pr_err("Failed to register. Unknown Error(%d).\n", rc);
++ break;
+ case -1:
+ printk(KERN_ERR "Failed to register firmware-assisted kernel"
+ " dump. Hardware Error(%d).\n", rc);
+@@ -387,18 +391,22 @@ static void register_fw_dump(struct fadu
+ case -3:
+ printk(KERN_ERR "Failed to register firmware-assisted kernel"
+ " dump. Parameter Error(%d).\n", rc);
++ err = -EINVAL;
+ break;
+ case -9:
+ printk(KERN_ERR "firmware-assisted kernel dump is already "
+ " registered.");
+ fw_dump.dump_registered = 1;
++ err = -EEXIST;
+ break;
+ case 0:
+ printk(KERN_INFO "firmware-assisted kernel dump registration"
+ " is successful\n");
+ fw_dump.dump_registered = 1;
++ err = 0;
+ break;
+ }
++ return err;
+ }
+
+ void crash_fadump(struct pt_regs *regs, const char *str)
+@@ -997,7 +1005,7 @@ static unsigned long init_fadump_header(
+ return addr;
+ }
+
+-static void register_fadump(void)
++static int register_fadump(void)
+ {
+ unsigned long addr;
+ void *vaddr;
+@@ -1008,7 +1016,7 @@ static void register_fadump(void)
+ * assisted dump.
+ */
+ if (!fw_dump.reserve_dump_area_size)
+- return;
++ return -ENODEV;
+
+ ret = fadump_setup_crash_memory_ranges();
+ if (ret)
+@@ -1023,7 +1031,7 @@ static void register_fadump(void)
+ fadump_create_elfcore_headers(vaddr);
+
+ /* register the future kernel dump with firmware. */
+- register_fw_dump(&fdm);
++ return register_fw_dump(&fdm);
+ }
+
+ static int fadump_unregister_dump(struct fadump_mem_struct *fdm)
+@@ -1208,7 +1216,6 @@ static ssize_t fadump_register_store(str
+ switch (buf[0]) {
+ case '0':
+ if (fw_dump.dump_registered == 0) {
+- ret = -EINVAL;
+ goto unlock_out;
+ }
+ /* Un-register Firmware-assisted dump */
+@@ -1216,11 +1223,11 @@ static ssize_t fadump_register_store(str
+ break;
+ case '1':
+ if (fw_dump.dump_registered == 1) {
+- ret = -EINVAL;
++ ret = -EEXIST;
+ goto unlock_out;
+ }
+ /* Register Firmware-assisted dump */
+- register_fadump();
++ ret = register_fadump();
+ break;
+ default:
+ ret = -EINVAL;
projects / thirdparty / kernel / stable-queue.git / commitdiff
